Abstract
| In many cases, the packing processes are considered as hybrid systems, consisting of a set of workstations, where various components must be processed, and at least one flexible transport system used for loading and/or unloading operations. This paper is focused to a Hybrid Petri Nets approach for modeling and simulation the behavior of such systems, considered a hybrid dynamic structure, with both continuous and discrete components interacting. For heuristic representation of the model, several sequences and rules were however followed. For the case study, starting from the structure of the system, in order to achieve a primary topology of the model, a bottomup synthesis technique was used, which allowed us to obtain a basic version, consisting in several sub-models of related physical subsystems of the packing station. Aggregation of these partial models was made in accordance with the interactions of the physical elements of the whole system, laid down in the operation protocol. Hence, into model topology various elements characteristic to generalized Petri Nets were used, with inhibitor arcs and test arcs, mainly aiming to reduce the complexity of the whole model. The validation of the model was done through on-line simulation, in various scenarios, under the Visual Object Net++ tool, which offers multiples facilities for the analysis of behavioral properties in various real operating conditions of the real physical system. Starting on the modular structure of the whole model, consisting in several submodels of the same type, the authors obtained a multilevel architecture, using Object Petri Nets paradigm for representation and exploiting their analysis potential. |
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